Back to Search Start Over

Independent and Combined Effects of Heatwaves and [PM.sub.2.5] on Preterm Birth in Guangzhou, China: A Survival Analysis

Authors :
Wang, Qiong
Li, Bing
Benmarhnia, Tarik
Hajat, Shakoor
Ren, Meng
Liu, Tao
Knibbs, Luke D.
Zhang, Huanhuan
Bao, Junzhe
Zhang, Yawei
Zhao, Qingguo
Huang, Cunrui
Source :
Environmental Health Perspectives. January, 2020, Vol. 128 Issue 1
Publication Year :
2020

Abstract

Background: Both extreme heat and air pollution exposure during pregnancy have been associated with preterm birth; however, their combined effects are unclear. Objectives: Our goal was to estimate the independent and joint effects of heatwaves and fine particulate matter [PM < 2.5 [micro]m in aerodynamic diameter ([PM.sub.2.5])], exposure during the final gestational week on preterm birth. Methods: Using birth registry data from Guangzhou, China, we included 215,059 singleton live births in the warm season (1 May-31 October) between January 2015 and July 2017. Daily meteorological variables from 5 monitoring stations and [PM.sub.2.5] concentrations from 11 sites were used to estimate district-specific exposures. A series of cut off temperature thresholds and durations (2, 3, and 4 consecutive d) were used to define 15 different heatwaves. Cox proportional hazard models were used to estimate the effects of heatwaves and [PM.sub.2.5] exposures during the final week on preterm birth, and departures from additive joint effects were assessed using the relative excess risk due to interaction (RERI). Results: Numbers of preterm births increased in association with heatwave exposures during the final gestational week. Depending on the heatwave definition used, hazard ratios (HRs) ranged from 1.10 (95% CI: 1.01, 1.20) to 1.92 (1.39, 2.64). Associations were stronger for more intense heatwaves. Combined effects of [PM.sub.2.5] exposures and heatwaves appeared to be synergistic (RERIs >0) for less extreme heatwaves (i.e., shorter or with relatively low temperature thresholds) but were less than additive (RERIs Conclusions: Our research strengthens the evidence that exposure to heatwaves during the final gestational week can independently trigger preterm birth. Moderate heatwaves may also act synergistically with [PM.sub.2.5] exposure to increase risk of preterm birth, which adds new evidence to the current understanding of combined effects of air pollution and meteorological variables on adverse birth outcomes. https://doi.org/10.1289/EHP5117<br />Introduction Preterm birth (PTB), defined as births with Previous studies suggested that heat stress during pregnancy can induce the hypersecretion of antidiuretic hormone (ADH) and oxytocin (OT), or dehydration, which [...]

Details

Language :
English
ISSN :
00916765
Volume :
128
Issue :
1
Database :
Gale General OneFile
Journal :
Environmental Health Perspectives
Publication Type :
Academic Journal
Accession number :
edsgcl.615360373
Full Text :
https://doi.org/10.1289/EHP5117